/*
 *  linux/fs/truncate.c
 *
 *  (C) 1991  Linus Torvalds
 */

#include "../include/linux/sched.h"
#include "../include/sys/stat.h"
//#include "../include/linux/fs.h"

static int free_ind(int dev,int block)
{
    struct buffer_head * bh;
    unsigned short * p;
    int i;
    int block_busy;

    if (!block)
        return 1;
    block_busy = 0;
    if (bh=bread(dev,block)) {
        p = (unsigned short *) bh->b_data;
        for (i=0;i<512;i++,p++)
            if (*p)
                if (free_block(dev,*p)) {
                    *p = 0;
                    bh->b_dirt = 1;
                } else
                    block_busy = 1;
        brelse(bh);
    }
    if (block_busy)
        return 0;
    else
        return free_block(dev,block);
}

static int free_dind(int dev,int block)
{
    struct buffer_head * bh;
    unsigned short * p;
    int i;
    int block_busy;

    if (!block)
        return 1;
    block_busy = 0;
    if (bh=bread(dev,block)) {
        p = (unsigned short *) bh->b_data;
        for (i=0;i<512;i++,p++)
            if (*p)
                if (free_ind(dev,*p)) {
                    *p = 0;
                    bh->b_dirt = 1;
                } else
                    block_busy = 1;
        brelse(bh);
    }
    if (block_busy)
        return 0;
    else
        return free_block(dev,block);
}

void truncate(struct m_inode * inode)
{
    int i;
    int block_busy;

    if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
          S_ISLNK(inode->i_mode)))
        return;
    repeat:
    block_busy = 0;
    for (i=0;i<7;i++)
        if (inode->i_zone[i]) {
            if (free_block(inode->i_dev,inode->i_zone[i]))
                inode->i_zone[i]=0;
            else
                block_busy = 1;
        }
    if (free_ind(inode->i_dev,inode->i_zone[7]))
        inode->i_zone[7] = 0;
    else
        block_busy = 1;
    if (free_dind(inode->i_dev,inode->i_zone[8]))
        inode->i_zone[8] = 0;
    else
        block_busy = 1;
    inode->i_dirt = 1;
    if (block_busy) {
        current->counter = 0;
        schedule();
        goto repeat;
    }
    inode->i_size = 0;
    inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}

